[This is pre-release documentation and subject to change in future releases. This topic's current status is: Milestone-Ready]

Topic Last Modified: 2010-07-16

In some cases you may need to use the distributed model, to implement SIP trunks at selected branch sites. To determine whether a SIP trunk is indicated for a branch site, review the Centralized vs. distributed SIP trunking section of How Do I Implement SIP Trunking?.

For information about the supported topology options for deploying SIP trunks in branch sites, see Branch-Site Voice Resiliency.

Example Branch Site SIP Trunk Requirements Analysis

The decision about deploying a branch site SIP trunk requires a site-specific cost analysis. For example, an enterprise that has a central site in Redmond, Washington and a branch site in New York should do an analysis to determine whether to implement a SIP trunk from the New York site to a local service provider (ORA).

Figure 1: Example Branch Site SIP Trunk

To determine whether a distributed SIP trunk in New York is cost-effective, identify which DIDs will use the SIP trunk, and analyze the number of calls New York makes to areas other than Redmond (425). If the cost of implementing a distributed SIP trunk is less than the cost of those calls, they should implement a SIP trunk at the branch site.